POLITICAL THEATER has reached ludicrous heights in Venezuela. For seven hours on Monday, the government in Caracas questioned a key opposition leader over her alleged assassination plot against President Nicolás Maduro; on Friday, it banned her from leaving the country. Three weeks before, the government had unveiled its latest fantasy through a dramatic news conference and colorful propaganda booklets, accusing 10 others — including the U.S. ambassador to Colombia — of complicity.

“I have been sentenced by those in power in Venezuela,” María Corina Machado, the opposition leader, wrote in El País two days before the questioning. “They tried to silence me with the blows I received a year ago while they attacked me, kicked me and fractured my face . . . and now they are attempting to annihilate me spiritually and physically.”

These concocted allegations are reminiscent of Hugo Chávez’s accusations against Ms. Machado’s vote-monitoring organization a decade ago. They are also the latest desperate attempt by Mr. Maduro to alienate more moderate protesters from Ms. Machado’s group and to distract Venezuelans from his government’s failures.

Over the past four months, protests against Mr. Chávez’s successors have decried food shortages, the suppression of free speech, inflation soaring above 60 percent and a stratospheric crime rate. Mr. Maduro has ordered his security forces to crack down on the protests. While some protesters have responded with violence, a Human Rights Watch report revealed that the government had committed an overwhelming amount of the abuses.

At least 42 people have died and 3,000 have been arrested. The opposition chief has been imprisoned since February. Negotiations between the government and opposition have stopped since the government refused to carry out the reasonable reforms proposed in the first round of talks.

The opposition has a tough road ahead, since the regime largely maintains control over the armed forces, legislature and judiciary. But there are signs of change. Mr. Maduro’s approval has dropped 18 percent a year since the last elections. Almost 70 percent believe the country is in bad shape. Venezuela’s Latin American peers have shifted from turning a blind eye to attempting mediation between the two sides.

Latin American countries should press Mr. Maduro harder to ease his repression, and the United States should act, too. The Obama administration has opposed imposing any sanctions on the grounds that they would destroy negotiations — but talks broke down anyway. If the administration fears that the comprehensive House sanctions bill might feed Mr. Maduro’s anti-American rhetoric, then it should draft a more targeted version focusing on leaders involved in the biggest human rights abuses.